Am 21.05.2013 um 17:41 schrieb Xan <dxpublica@telefonica.net>:

> Hi,
> 
> I have two enumerations:
> 
>  \defineenumeration
>   [exercici]
You need a different name for the normal enumeration environment, e.g. exercicidefault
>   [alternative=serried,text={\startcolor[middlecyan]Exercici\stopcolor},stopper={.\space},left={\bgroup},right={\egroup},width=fit,headstyle=\ss]
> 
> \defineenumeration
>   [exercicivora]
>   [alternative=serried,text={\startcolor[middlecyan]Exercici\stopcolor},stopper={.\space},left={\bgroup\startframedtext[background=screen,frame=off,width=broad]},right={\stopframedtext\egroup},width=fit,headstyle=\ss]
> 
> 
> I just want to join into one: when I do \startexercici ...      \stopexercici ConTeXt do the first, and when I pass \startexercici[vora] ... \stopexercici then do the second. That is, 'vora' as optional argument.
> 
> How can I achieve that?

You have to write you own version of the exercise environment which chooses one the two enumerations dependent on the argument.

\def\startexercici
  {\dosingleempty\dostartexercici}

\def\dostartexercici[#1]%
  {\edef\currentexercici{#1}%
   \doifelse{\currentexercici}{vora}
     \startexercicivora
     \startexercicidefault}

\def\stopexercici
  {\doifelse{\currentexercici}{vora}
     \stopexercicivora
     \stopexercicidefault}

Wolfgang